When charging a dry supply line, what component must be opened?

• A. The discharge valve
• B. The bleeder valve
• C. The priming valve
• D. The pressure relief valve

Answer: (B)

When charging a dry supply line, it is essential to open the bleeder valve. The purpose of the bleeder valve is to allow air to escape from the supply line as it begins to fill with water. If this valve is not opened, air can become trapped in the line, preventing water from flowing properly and potentially causing issues with pressure and water delivery to the fire scene.

Opening the bleeder valve ensures that the line is charged effectively and that any air present is expelled, which is crucial for the proper operation of the overall firefighting system. This step helps maintain the efficiency and readiness of the water supply for firefighting efforts.

Other components mentioned, such as the discharge valve and pressure relief valve, serve different functions and do not directly aid in the charging process of a dry supply line. The discharge valve is primarily involved in delivering water from the apparatus, while the pressure relief valve is designed to prevent excessive pressure build-up in the system, not to facilitate the initial filling of the line.